<template>
  <!-- 商品分类导航 -->
    <div class="type-nav" >
        <div class="container" >
            <div @mouseleave="moveOutDiv" @mouseenter="isShow=true">
                <h2 class="all">全部商品分类</h2>
                <transition name="sort">
                    <div class="sort" v-show="isShow">
                        <div class="all-sort-list2" @click="toSearch($event)">
                            <div class="item"  
                                :class="{ item_on: currentIndex===index}"
                                v-for="(c1,index) in categoryList" 
                                :key="c1.categoryId"
                                @mouseenter="moveInItem(index)"
                            >
                                <h3>
                                    <!-- <a href="">图书、音像、数字商品</a> -->
                                    <!-- 自定义属性 -->
                                    <a 
                                        href="javascript:;" 
                                        :data-category1Id="c1.categoryId"
                                        :data-categoryName="c1.categoryName"
                                    >{{c1.categoryName}}</a>
                                    <!-- 把所有a标签换成routerlink 这样组件标签太多 导致内存中组件对象很多  -->
                                    <!-- <router-link 
                                    :to="{
                                    name: 'search',
                                    query: {
                                        category1Id: c1.categoryId,
                                        categoryName: c1.categoryName,
                                    }, 
                                    }">{{c1.categoryName}}</router-link> -->

                                    <!-- 改为编程式导航 但是内存中会定义很多函数-->
                                    <!-- <a href="javascript:;"
                                        @click="
                                            $router.push({
                                                name: 'search',
                                                query: {
                                                    category1Id: c1.categoryId,
                                                    categoryName: c1.categoryName,
                                                }, 
                                            })
                                            "
                                            >{{c1.categoryName}}</a> -->
                                </h3>
                                <div class="item-list clearfix">
                                    <div class="subitem">
                                        <dl class="fore" v-for="(c2,index) in c1.categoryChild" :key="c2.categoryId">
                                            <dt>
                                                <a 
                                                    href="javascript:;"
                                                    :data-category2Id="c2.categoryId"
                                                    :data-categoryName="c2.categoryName"
                                                    >{{c2.categoryName}}</a>
                                            
                                            </dt>
                                            <dd>
                                                <em v-for="(c3,index) in c2.categoryChild" :key="c3.categoryId">
                                                    <a 
                                                        href="javascript:;"
                                                        :data-category3Id="c3.categoryId"
                                                        :data-categoryName="c3.categoryName"
                                                        >{{c3.categoryName}}</a>
                                                    
                                                </em>
                                                
                                            </dd>
                                        </dl>
                                    </div>
                                </div>
                            </div>
                        </div>
                    </div>
                </transition>
            </div>
        
            
            <nav class="nav">
                <a href="###">服装城</a>
                <a href="###">美妆馆</a>
                <a href="###">尚品汇超市</a>
                <a href="###">全球购</a>
                <a href="###">闪购</a>
                <a href="###">团购</a>
                <a href="###">有趣</a>
                <a href="###">秒杀</a>
            </nav>
            
        </div>
    </div>
        
</template>

<script>
  import {mapState} from 'vuex'
    //   import _ from 'lodash'   // 这样会讲整个lodash引入
  import throttle from 'lodash/throttle'
  export default {
    name:'TypeNav',
    data() {
        return {
            currentIndex: -1,
            isShow: true,
        }
    },
    methods: {
        // 未节流
        // 移动到当前分类标签
        // moveInItem(index){
        //     this.currentIndex = index
        //     console.log(index);
        // }

        // 节流后  注意这里不能写箭头函数 因为这里箭头函数this指向不是组件对象
        moveInItem: throttle(function(index){
            this.currentIndex = index
            // console.log(index);
        },20,{ 'trailing': false }),

        // 事件委派的回调函数
        toSearch(event){
            // console.log(event);
            // 获取目标元素  真正的点击元素
            // let targetNode = event.target
            
            // 获取当前目标元素身上 data-属性 组成的对象
            let data = event.target.dataset
            // console.log(data);
            let {category1id,category2id,category3id,categoryname} = data
            
            // 如果categoryname存在 则点击的是a标签
            if(categoryname){
                let location = {
                    name: 'search'
                }
                let query = {
                    categoryName:categoryname
                }

                // 确定是一级标签、二级标签还是三级标签
                if(category1id){
                    query.category1Id = category1id
                }else if(category2id){
                    query.category2Id = category2id
                }else{
                    query.category3Id = category3id
                }
                
                

                // 找到所有的query参数后 放到location里面
                location.query = query

                // 跳转之前查看有无params参数  有合并 params参数
                if(this.$route.params){
                    // console.log(this.$route.params);
                    location.params = this.$route.params
                }

                // this.$router.push(location)
                // home 跳转到 search 用push   search页内跳转用 replace  通过路由路径来进行判断
                if(this.$route.path !== '/home'){
                    this.$router.replace(location)
                }else{
                    this.$router.push(location)
                }

            }
        },
        // 移出分类时 隐藏
        moveOutDiv(){
            this.currentIndex = -1
            // 判断不在 home 组件时  隐藏分类
            if(this.$route.path !== '/home'){
                this.isShow = false
            }
        }
    },
    // 组件挂载完成后 立马发起请求  存储到vuex 而不是vue组件里面
    mounted() {
        // 触发  本质就是在调用指定的 actions 函数 
        // home 和 search切换时 会重新创建 typeNav组件  mounted会重新挂载 就会再重新发请求
        // this.$store.dispatch('home/getCategoryList')
        // this.$store.dispatch('getCategoryList')
        // 判断不在 home 组件 则隐藏分类
        if(this.$route.path !== '/home'){
            this.isShow = false
        }
    },
    // 将vuex的数据放到vue组件中使用 
    // state和getters 是在computed中操作
    // mutations和actions是在 methods 中操作
    computed: {
        // categoryList(){
        //     return this.$store.state.home.categoryList
        // },
        ...mapState(['name']),
        // ...mapState({ 
        //     categoryList:state => state.home.categoryList
        // })
        ...mapState('home',['categoryList'])        
    }
  }
</script>

<style lang="less" scoped>
    .type-nav {
        border-bottom: 2px solid #e1251b;

        .container {
            width: 1200px;
            margin: 0 auto;
            display: flex;
            position: relative;

            .all {
                width: 210px;
                height: 45px;
                background-color: #e1251b;
                line-height: 45px;
                text-align: center;
                color: #fff;
                font-size: 14px;
                font-weight: bold;
            }

            .nav {
                a {
                    height: 45px;
                    margin: 0 22px;
                    line-height: 45px;
                    font-size: 16px;
                    color: #333;
                }
            }

            .sort {
                position: absolute;
                left: 0;
                top: 45px;
                width: 210px;
                height: 461px;
                position: absolute;
                background: #fafafa;
                z-index: 999;

                &.sort-enter,&.sort-leave-to{
                    height: 0;
                    opacity: 0;
                }
                &.sort-enter-to,&.sort-leave{
                    height: 461px;
                    opacity: 1;
                }
                &.sort-enter-active,&.sort-leave-active{
                    transition: all 0.3s;
                }

                .all-sort-list2 {
                    .item {
                        h3 {
                            line-height: 30px;
                            font-size: 14px;
                            font-weight: 400;
                            overflow: hidden;
                            padding: 0 20px;
                            margin: 0;

                            a {
                                color: #333;
                            }
                        }

                        .item-list {
                            display: none;
                            position: absolute;
                            width: 734px;
                            min-height: 460px;
                            background: #f7f7f7;
                            left: 210px;
                            border: 1px solid #ddd;
                            top: 0;
                            z-index: 9999 !important;

                            .subitem {
                                float: left;
                                width: 650px;
                                padding: 0 4px 0 8px;

                                dl {
                                    border-top: 1px solid #eee;
                                    padding: 6px 0;
                                    overflow: hidden;
                                    zoom: 1;

                                    &.fore {
                                        border-top: 0;
                                    }

                                    dt {
                                        float: left;
                                        width: 54px;
                                        line-height: 22px;
                                        text-align: right;
                                        padding: 3px 6px 0 0;
                                        font-weight: 700;
                                    }

                                    dd {
                                        float: left;
                                        width: 580px;
                                        padding: 3px 0 0;
                                        overflow: hidden;

                                        em {
                                            float: left;
                                            height: 14px;
                                            line-height: 14px;
                                            padding: 0 8px;
                                            margin-top: 5px;
                                            border-left: 1px solid #ccc;
                                        }
                                    }
                                }
                            }
                        }

                        // &:hover {
                        //     background-color: pink;
                        //     .item-list {
                        //         display: block;
                        //     }
                        // }
                        &.item_on {
                            background-color: pink;
                            .item-list {
                                display: block;
                            }
                        }
                    }
                }
            }
        }
    }
</style>